Strobilurin resistance in Alternaria solani (potato early blight) survey for Michigan

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Strobilurin-insensitive isolates of Alternaria solani were reported by Dr. Neil Gudmestad (North Dakota State University) for samples of the disease taken from potato fields in southwest Michigan and Dr. Walt Stevenson (University of Wisconsin) for samples taken in Tuscola County, Michigan in 2005. In 2006, it is intended to widen this survey to all potato growing regions of Michigan. Samples should be collected and mailed to Dr. Willie Kirk, MSU (address below). These samples will be divided and sent to NDSU and UW for analyses as part of a wider North Central region survey.

Sampling protocol

  1. Individual leaf samples should be cut from the main stem and folded into a dry paper towel.
  2. Ten leaf samples per field will be adequate.
  3. The paper towels containing the leaves should be placed into a zip-lock sandwich bag and labeled with the following information:
  • Variety
  • Location, township, county
  • Field ID
  • Number of applications of Group 11 fungicides (Quadris, Headline, Gem, Tanos and Reason)
  • Date and contact ID – name will be fine.

We hope to collect as many samples as possible for Michigan. The samples should be sent to:
Dr. Willie Kirk
35 Plant Biology Building
Plant Pathology
Michigan State University
East Lansing, MI 48824, USA
Phone 517-353-4481, Mobile 517-775-6048

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